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Mon, 10 Nov 2025 07:43:38 -0800 (PST) From: Xie Yuanbin To: arnd@arndb.de, david@redhat.com, tglx@linutronix.de, segher@kernel.crashing.org, riel@surriel.com, peterz@infradead.org, linux@armlinux.org.uk, mathieu.desnoyers@efficios.com, paulmck@kernel.org, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, davem@davemloft.net, andreas@gaisler.com, luto@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, james.clark@linaro.org, anna-maria@linutronix.de, frederic@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, nathan@kernel.org, nick.desaulniers+lkml@gmail.com, morbo@google.com, justinstitt@google.com, qq570070308@gmail.com, thuth@redhat.com, brauner@kernel.org, jlayton@kernel.org, aalbersh@redhat.com, akpm@linux-foundation.org, david@kernel.org, lorenzo.stoakes@oracle.com, max.kellermann@ionos.com, ryan.roberts@arm.com, nysal@linux.ibm.com, urezki@gmail.com Cc: x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-perf-users@vger.kernel.org, llvm@lists.linux.dev, will@kernel.org Subject: Re: [PATCH v2 3/4] Provide the always inline version of some functions Date: Mon, 10 Nov 2025 23:43:01 +0800 Message-ID: <20251110154301.1930-1-qq570070308@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Sun, 09 Nov 2025 18:35:23 +0100, Arnd Bergmann wrote: > You can mark the caller as __attribute__((flatten)) to force all > functions to be inlined into that one if possible. I don't know > if that would be helpful or desired here though. Thanks, you made me aware of this attribute for the first time, it is really a great attribute, and it has been already added to the kernel public header. However, it's rarely used in the kernel, which I really think is a pity. Perhaps, I can try adding this attribute to some hot functions in another patch. For this patch, I think this is sufficient. There are some cold if branches inside `__schedule`, __flatten will inline the function calls in this part of the code, which may cause some unexpected performance degradation. > Arnd Xie Yuanbin